Apparatus for vulcanizing.



w. c. MERRILL. APPARATUS FOR VULCANIZING.

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unir stars r WILLIS C. MERRILL, OF BOSTON, MASSACHUSETTS, ASSIGNOR, BY MESNE ASSIGNMENTS, TO THE MERRILL PROCESS COMPANY, 0F BOSTON, MASSACHUSETTS, A CORPORATION OF MASSACHUSETTS.

Specification of Letters Patent.

APPARATUS FOR VULCANIZING.

Patenten Dee. io, wie.

Application led July 15, 1915. Serial No. 40,076.

of Massachusetts, have invented certain new and useful Improvements in Apparatus for Vulcanizing, of which the following is a specification.

My invention relates to a method of and apparatus for vulcanizing rubber goods.

The main object of my invention is the use of a circulating heating fluid having a boiling point above 212o F. and a carbonizing point higher than the temperature required forthe proper vulcanization of the goods under treatment, and by the use of such circulating heating fluid high temperatures are produced, while the pressure of the circulating heating fiuid is negligible.

Another object is to control the temperature of the circulating heating fiuid so that when it reaches a predetermined maximum point suitable for the proper vulcanization of the goods then any further increase in temperature of said circulating heating fluid through the vulcanizer is cut olf until the temperature of the circula-ting heating uid drops to the predetermined maximum point, when the apparatus employing my improved method will automatically operate to circulate the circulating heating fluid through the vulcanizer, and will so continue until the temperature of the circulating heating fluid again reaches the predetermined maximum point when the operation is repeated as above described.

by the apparatus hereinafterdescribed and' illustrated in the claims, and in which my improved method of vulcaniZing is carried out.

In the accompanying drawings which illustrate a construction in which my improved method is carried out:

Figure 1 is a. side elevation with the vul-Z canizer in section and in which my improved method is employed.

Fig. 2 is a detail sectional View of the thermostatic device controlling the flow of fuel to the gas of' fuelburner.

Fig. 3 is a longitudinal view partly in section through the upper end of the vulcanizer on the line X-X, Fig. 1, and showing the upper plate for diverting and guiding the' flow of the circulating heating fluid, with the heating coil omitted.

Like letters of reference refer to like parts throughout the several views.

The heating medium used in this apparatus preferably is a petroleum or other suitable oil unaffected by high temperatures and of high carbonizing point and is supplied to the apparatus from the supply or expansion tank 1 through the pipe 2 and is drawn in and forced by the pump 3 into the pipe 6 thence into the heater 8 where the pipe 6 is coiled as shown at 7 to increase the heating surface thereof. The products of combustion pass out from the heater through the stack 24. The heated oil then passes out into the pipe 6 and through thethermostatic` device 11 into the pipe 13 and thence into the jacket 14 of the vulcanizer. The circulating heating oil passes, as indicated in Fig. 3 by the arrows, around the vulcanizing chamber 27 to the ports 44 of the oil diverting plate 41 and down through said ports 44 to the ports 45 in the oil diverting plate 42 and thence through the ports 46 in the oil diverting plate 43 to the bottom of the jacket 14 around the vulcanizing chamber 27 and thence out through the pipe 15 through the thermostatic device 16 to the pump 3 so that the circulation of this heated oil is continued through the apparatus bv means of ture of the circulating heating fluid in the pipe 6 is below a predetermined point the :fuel will flow to the burner 9, but upon the temperature of the circulating heating fluid flowing through the pipe 6 reaching a'l predetermined point the thermostatic device 11 will operate to shut off the supply of fuel to the burner 9, and upon the temperature of the circulating heating fluid fiowing through the pipes 6 and y13 falling below a predetermined maximum point the thermostatic device 11 will automatically operate to allow the fuel supply to again pass to the burner 9. This thermostatic device consistsof the box 11 with the usual spring 39 to I for properly heating soft and hard rubber goods without injury respectively, and as long as the temperature of the circulating heating fluid flowing through the pipe 6 into the pipe 13 and through the rest of the vulcanizingV apparatus is below 2750 F. or 3050 F., as above mentioned, more or less, the parts will be in the position shown in Figs. 1 and 2 with the valve 37 open to allow communication for the fuel supply through the pipe l0 and thence into the burner 9. Now, if the temperature of' this circulating heating fluid passing through the pipes 6 and 13 reaches 2750 F. or 3050 F., respectively, for soft or hard rubber goods or higher the thermostatic spring 39 will eX- pand and move the valve 37 outwardly and close the fuel supply through the pipe 10 and remain so as long as the temperature remains at 2750 -F. or 3050 F., respectively, or above. Now, if the temperature falls below the degrees above mentioned the thermostatic spring 39 will automatically contract and bring the parts back in a. position shown in Fig. 2, so that the passage is free for the supply of fuel through the pipe 10 to the burner 9. The pump 3 is driven by the belt 5 operated by the electric motor 4 which is in circuit with the rheostat 48 on which is pivoted the rheostat arm 23 connected in turn by the link 21' with lever 20 pivoted at 19 and connected at its outer end to the stem 18 secured to the thermostatic spring 17 of the thermostat 16. The rheostat is connected by the wires a and a to a suitable source of electricity. Y

To heat the interior chamber 27 of the vulcanizer 47 the circulating heated oil Y passes from the pipe 13 into the pipe 25 controlled by the valve 26 .and thence through the coils 28 and out through the pipe 29. controlled by the valve 30 into the pipe 15 where the circulating oil from the ]acket 14 and the circulating oil in the coils 27 meet and return to the pump 3.

With the thermostat set for a maximum temperature of 27 50 F. or 3050 F more or less, as the case maybe, for the circulating fluid, the thermostatic device 16 and the connecting parts will be in the position shown in Fig. 1 with the circulating heating fluid returning through the pipe 15 passing through the thermostatic device 16 in the pump 3 and thence into the pipe 6 through the heater 8, thermostat 11 and vulcanizer 47 and then back to the pump and as long inermi as the temperature remains below 2750 F. or 3050 F., more or less, as the case may be, this circulation is automatically kept up. Now if the temperature of the circulating heating fluid returning through the pipe 15 to the pump 3 should reach 2750 F. or 3050 F. or above, then the thermostatic spring 17 will eXpand and Operate the stein 18, lever 19 and rheostat arm 22 so as to move the inner end 23 of the rheostat arm 22 upwardly, throwing in more resistance and stopping the motor, thereby saving power until the temperature drops below the predetermined maximum point. In such a case, if the temperature of the circulating heating fluid passing through the thermostat 16 should drop below 27 50 F.` or 3050 F., as the case may be. then the inner end 23 of the thermostatic arm 22 will drop back over the contact points of the rheostat 48 and cut out the resistance andrestart the motor so as to operate the pump 3 to its full capacity for circulating the circulating heating fluid. This operation of circulating the circulating heating fluid will be automatically kept up by the pump 3 as long as the temperature of the circulating heating Huid remains below the temperature required, 2750 F. or 3050 F., as the case may be, in this class of apparatus.

In this class of apparatus as long as the temperature remains below the predetermined maximum temperature, say 2750 F. or 3050 F., suitable for the articles being vulcanized, then the pump 3 is kept in operation to keep up the circulation of the circulating heating fluid, but if the temperature of the circulating heating fluid reaches 275O F. or 3050 F. or above, then, as above described, the motor stops, and the pump is shut down so that the circulation of the circulating -lieatinp fluid through the vulcanizer 47 is cut off until the temperature of the circulating heating fluid falls below a predetermined maXimum point, say about 2750 F. or 3050 F., as the case may be, when the operation' is repeated.

Instead of entirely stopping the motor 4 and the pump 3 When the temperature reaches a predetermined maximum point, say 2750 F. or 3050 F., as the case may be, the rheostat maybe so arranged as to slow down the motor 4 and pump 3 so thatthere will be a slow circulation of the circulating heating fluid through the vulcanizer 47, but with the fuel supplyllto the burner cut ofl' at this -heating iiuid drops below 275 F; or 305 F.,'as the case may be, the supply of fuel will .again be admitted to the burner 9.

In thisY apparatus the oil used as the circulating heating Huid has a boiling'point above 212 F. and may be heated to a high temperature, vsay 300 F. or higher, with a negligible pressure, say 5 to 10 lbs. to lthe .square inch, which pressure is due not to the temperature of the circulating heating luid,'but to the friction due to the flow ofV the' oil through the pipes and other parts of the apparatus, and this frictional pressure escapes to the atmosphere through the expansion tank 1 which relieves this pres- "sure in the system. By the use of this circulating heating iuid there is produced A high temperaturesv and low pressure, as

tion and in its transit it is-brought into cons tact with high temperatures such as would be produced by burning fuel oil, kerosene,

gas or other suitable vheat producing 'material,fand thiscirculating heating fluid is advanced or pushed forward by the circulating pump and the heat units stored in this heating uid medium are transferred from the heating medium `to the article being vulcanized.

By this forced or accelerated f :irculation `of the heating oil, new surfaces are more frequently presented to the heat producing device and thereby high temperatures are more economically used in the production ofthe heat units,'and further by this circulation the circulating heating oil. is prevented fro becoming over heated or carbonized, an because of its velocity there is a uniform How of heat to all the supericial area of the heating surfaces. which give off a uniform heat to the material. under treatment. e

rlhe advantage of this ycontinuous circulation consists in usin a heating fluid medium which does not con ense at a low temperature and does not concentrate the heat be cause the heat units stored in the circulatingheating fluid are under control and the temperature, of the circulatin heating iiuid at no time v reaches a point wit injury tothearticlevk subjected ,to the proper degree of heat.

AThel great advantage in using acirculating heating Huid having a higher' boiling A point than water'liesin the fact that by this means heat can be conveyed -Without vaporization and'it is possible to get higher temperatures than it is practicaliand safe to get with steam. The further advantage of usingv a fluid with a high boilin point is that more `heat units `are store A livered in a given time without condensation loss, also the freedom from excessive pressure removes the. danger attending the use of steam as a-heating'fluid medium.

In this apparatus embodying my invention', there is an automatic regulation of the fuel supplyto the burner andan automatic and deregulation of the circulation of the circulatl V ingl heating fluid both controlled by the temperature of said circulating heating iiuid, or any suitable hand operated controlllng devies may be used to regulate the vdegree of temperature required, to obtain the bestl results.

This circulating heatin oil -used as a heating iuid medium in 't is system has a boiling point above'212 F. and also a carbonizing point higher than the temperature required to properly dry the article under treatment, so that in its circulation it imparts to the article under treatment heat at high temperatures without gasifying, as in the case of steam, and to impart temperatures higher than is practicable lwith steam,

thereby enabling the said circulating heating oil-`medium to be heated to high .temperatures without vcarbonization and the .consequent deposit of carbon on-the inner lsurfaces of the' conduit. vSuch' depositsv of carbon on the interior of the heating conduit or coil prevent the 'easy iow of the heating oil and the ready transmission of" heat 'to the article under treatment on accounty ofthe obstruction in the conduit by the' carbon deposits and of the increased density of the circulating heating fluid by the forming of carbon 1n the circulating heating oil, and the integrity of the heating coil or conduit by such deposits of car,

bon 'is endangered because the heat gen- Y erated by the external heater is not readily accepted by the circulating heating oi] medium and thereby causes a burning or' crystallizing of the heating conduit orcoil"T all of which diiiiculties are obviated by the use of a circulating heating oil whose-carbonizing point is higher than the temperature required forthe proper heating of the article under treatment. 't

n practice by this system` nomaterial loss of this circulating heating uidmedium of high boiling point and high carbonizing pointV occurs,` as the temperature at which vaporization `would take place is not apfrom a condensable elasticv fluid like steam proachedand the circulating heating iuid' -niedium being anon-elastic liquid differs 125 andmay be used over and over again for heating the material under treatment.

While I have disclosed my invention as employed in a vulcanizing apparatus as yet it will be understood that it may be applied to other heating devices used in the treatment of rubber.

While temperatures for soft rubber goods of 255 F. to 275o F. or 280 F. and for hard rubber goods from 275-o F. to 305o F. have been found in practice to produce excellent `results in vulcanization, yet any other temperatures found suitable for the goods under treatment may be employed and the thermostatic devices accordingly set.

After the goods for vulcanization are placed Within the chamber 27 the door 31 .la is closed and secured firmly in positio'n in any suitable manner to form an air tight chamber 27 during the vulcanization of the rubber goods.

In starting up the apparatus the oil in the system may be cold and viscous and it requires a great pump pressure to start the circulation of the heating fluid medium,`so that in case undue pressure is exerted by the pump, the pipe 40 Will take care of such pump pressure and allovv the overflowv back into the expansion tank l and thus relieve this pump pressure from the rest of the sys- 'tem until the circulating fluid is heated,

after Which the pressure is slight and not due to the temperature of the heating oil, but is only due to its friction in flowing through the pipes. The pipe 40 may be Hexible if necessary, so as to vary the heat pressure due to the pump, that is, for instance, if there is a Working `pressure of 20 lbs. in the system due to the pressure of the pump by .lowering the flexible pipe 40, the pressure could be reduced to say l5 lbs., or by raising the flexible pipe the pressure could be increased as deslred. l

The vulcanizing chamber is provided with a suitable pressure gage 36, relief valve 35 and suitable thermometer 34.

What I claim as my invention and desire to secure by Letters Patent of the United States, is: p Y 1. In a vulcanizing apparatus, a closed chamber for the articles to be vulcanized, a heating fluid supply, a continuous conduit for receiving said heating fluid and through which said heating fluid iis circulated to transmit its heat by radiation to the articles being vulcanized, means for circulating said fluid through said conduit, means for heatin said heating Huid' circulating through said conduit, and automatic means for controlling the circulation of said circulating heating fluid through said conduit.

2. Ina vulcanizing apparatus, a closed chamber for thearticles to be vulcanized, a

heating fluid supply, a continuous conduit for receiving said heating fluid and through which said heating fiuld is circulated to transmit its heat by radiation to the articles bein vulcanized, means for circulating said heating fluid through said conduit, means for heating said heatin fluid circulating through said conduit, an automatic means for controlling the circulation of said circulating heating fluid through said conduit by the temperature of the said heatingfluid circulating Within said conduit.

3. In a vulcanizing apparatus, a closed chamber for the articles to be vulcanized, a heating fluid supply, a continuous conduit for receiving said heating fluid and through which said heating fluid isl circulated to transmit its heat by radiation to the articles being vulcanized, means for circulating said heating fluid througly'said conduit, means for heating said heating fluid circulating through said conduit, a motor for operating through which said heating fluid is circu.

lated to transmit its heat by radiation to the articles being vulcanized, means for circulating said heating fluid through said conduit, means for heating said heating fluid circulating through said conduit, a motor for operating said fluid circulating means, and automatic motor controlling mechanism for regulating the circulation of said circulating heating fluid through said conduit. 5. In a vulcanizing apparatus, a closed chamber for the articles to be vulcanized, a heating fluid supply, a continuous conduit for receiving said heating fluid and through which said heating fluid is circulated to transmit its heat by radiation to the articles being vulcanized, means for circulating said heating fluid through said conduit, means for heating said heating fluid circulating through said conduit, a motor for operating said fluid cirCulatingmeanS, and automatic motor controlling mechanism for regulating the circulation of said circulating heating fluid through said conduit and controlled by the temperature of the said heating fluid circulating Within said conduit.

6. An apparatus for treating articles by heat comprismg a chamber to inclose said articles and a body of air, a continuous conduit extending 1nto said chamber and exterlor thereof, means to apply heat to a portion of said conduit exterior of saidchamber; a viscous heat carrying medium completely filling said conduit and adaptedV t0 retain its normal condition unoder any 5 temperature to be utilized in said chamber,

and a pump connected with said conduit and .adapted to propel said heat carrying medium 

